Lumbosacral and Spinopelvic Anatomy and Pathology - Right S1 Joint

Axial Closeup View of the Right SI Joint

Axial closeup view of the right SI joint,
a few millimeters cranial to the level of Slide 21. There is a
dramatic change in configuration and orientation of the joint space.
The subchondral bone of the ilium is considerably thicker than that
of the sacrum and carries a ridge posteriorly. Behind this ridge a
synovial cyst in the iliac bone comes into view, the cyst
communicates with the SI joint cavity and is delimited from the
cancellous bone by a thin shell of condensed bone. Due to
positioning of the cadaver, the sacrum is slightly subluxed
anteriorly, stretching the anterior joint capsule and unfolding the
joint recess. The lumbosacral trunk is located 2cm medial to the
joint space.